Aqua-(propane-dioato-κO,O)[2-(1H-pyrazol-1-yl-κN)-1,10-phenanthroline-κN,N']nickel(II) trihydrate.

In the title mononuclear complex, [Ni(C(3)H(2)O(4))(C(15)H(10)N(4))(H(2)O)]·3H(2)O, the metal center is coordinated in a distorted NiN(3)O(3) geometry. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the components into a two-dimensional network. In addition, there are weak π-π stacking inter-actions between symmetry-related phenanthroline rings, with a centroid-centroid distance of 3.6253 (17) Å.